Automatic telephone system



J. H. HOMRIGHOUS.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED MAR. 10. I919.

Patented May 17,1921

Julm HHmrz OFFICE.

JOHN H. HOMRIGHOUS, OAK PARK, ILLINOIS, ASSIGNOR T0 AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS,

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented May 1'7, 1921.

Application filed March 10, 1919. Serial No. 281,763.

matic telephone systems and more particu;

larly to such systems as comprise amain exchange and one or more branch exchanges.

More specifically my invention has for its principal object the provision of an improved connector switch having access to a plurality of groups of lines, which connector switch is provided with an auxiliary switch controlled by a single digit to pick out a set of wipers corresponding to a group of lines and also to select a particularly ringinzg generator when a line in a party line group is called.

Another object is the provision of an auxiliary switch controlled by a single digit to select a group of trunks to the main exchange and to then automatically select an idle trunk in that group.

Allthe foregoing improvements together with others not now specifically mentioned,

will be fully explained hereinafter; reference being had to the drawing. In the drawing the fi ire shows a substation A, a line switch individual to the line of substation A, and a connector switch D accessible to the line switch C. This substation A may be of any approved automatic type such for example as the substation shown in the British patent to Martin No.

1419 of 1910. As represented herein it coinprises essentially the receiver 4, transmitter 3,; switch hook 7, ringer 5, and condenser 6.- Being an automatic substation it is also provided with a pair of impulse sprmgs 8 and 9 which may be controlled by an impulse wheel through the medium of a finger hole dial (not shown). The line conductors 10 and 11 of the substation A terminate in an individual switch C. The line switch 0 maybe of the general type of line switch shown in U. S. Letters Patent No. 1,126,727 granted February2, 1915 to Dietl. Through the medium of the line switch (I the line of substation A when-calling is given access to a plurality of trunk' lines extend ng connector switches.

One of the trunk lines to which the line switch C has access is shown extending to the connector switch I). The connector switch D, may be-of the general type of connector switch disclosed in U. S. Letters Patent No. 815,176 granted March 13, 1906, to Keith, Erickson and Erickson, except that it is provided withan elongated shaft and three set of bankcontacts, each set containing terminals of one hundred lines. It is also provided with an auxiliary switch which switch is controlled by the first digit to pick out a set of wipers and a particular ringing generator when the called subscriberv is in a party line group. Also the auxiliary switch iscontrolled by a single digit to select an idle trunk to the main exchange,- all of which will be more fully hereinafter described.

While I have shown throughout the'drawing a plurality of batteries, it is to be understood that there is preferably but one battery having its positive pole grounded. Associated with the connector D I have shown a ringing equipment H and a busy signaling machine I. This apparatus may be the usual type, such as is found in well known telephone systems.

Having briefly described the apparatus involved, I will now proceed to explain more in detail the operation of the same.

When the subscriber at substation A removes his receiver a circuit is closed at the switch hook springs for the line relay 14 of the switch C in series with the line circuit. Relay 14, upon energizing, closes a circuit at springs 15, including switching relay 16, and the rotary magnet 17 in series, and at the same time prepares a circuit for the rotary magnet 17 at springs 18 to the private wiper. 20. Suppose the trunk line upon which the wipers 19, 20 and 21 are resting i busy, then a ground potential is present on the private contact-corresponding to that trunk. This ground potential will short the high resistance relay 16 and energize the rotary magnet 17 to step the wipers to the contacts of the next trunk line. If this trunk line is busy the rotary magnet will again be energized and this operation will con tinue until an idle trunk is reached, at which time there will be no ground potential presout at the contact which the private wiper meets. Relay 16 .will be no longer shorted.

out and will immediately energize over the series circuit hereinbefore traced to extend the line'of substation A to a trunk line leading to a connector switch. Suppose the first idle trunk-line is the trunk line 22, 23 and 24 leading to the connector switch D. Relay 16, upon energizing, closes a circuit for the double wound relay 25 of the connector D in series with the line circuit and wipers l9 and 21. Relay 25 upon energizing, closes a circuit for the slow acting release relay 26. Relay 26, upon energizing, closes a holding circuit for the relay 16 of the line switch C, which may be traced as follows from. ground at G, springs 27 and 28, conductor 23, wiper 20, springs 29, winding of relay 16 through the winding of rotary magnet 17 to battery. Since the line relay 14 is slow acting it retains its armature to maintain the winding 16 energized until after the above holding circuit has been established. A branch of the holding circuit extends by way of conductor 32 to multiple test contacts in the banks of connector switches having access to the line of substation A, whereby a ground potential on these test contacts the said line is made busy,

The foregoing operations have occurred in response to the removal of the receiver at the substation A. The calling subscriber may now proceed to manipulate. his calling device in accordance with the first digit of the desired number, thereby producing in the usual and well known manner a series of interruptions in this line circuit. At each interruption the line relay 25 denergizes momentarily and sends an impulse of current to-the stepping magnet 34 of the auxiliary switch over the following path: from.

ground at G through springs 35, springs 36, winding of slow relay 37, springs 38, springs 39 and 57 and winding of magnet 34 to battery. In response to these impulses the magnet 34 operates to step the wipers 40, 41, 42 and 43 of auxiliary switch to a set of contacts in the bank of the auxiliary switch in which terminate a set of the connector wipers] The first set of the connector wipers 44, 45 and 46 have access to one group of lines .while the second set of wipers 47, 48 and 49 have access to another group of lines The third and fourth sets of contacts in the bank of the auxiliary switch corresponding to the line and test contacts are multipled together and terminate in a third set of wipers which have access to group of party lines. The remaining sets of contacts terminate. in

Y switches C which switches are in all -re= closes a circuit for switching 53 over the following path: from ground at G contact engaged by the wiper 42, and said wiper, springs 55 and 101, springs 54, winding of relay 53, springs 56, winding of magnet 34 to battery. Magnet 34 is of low resistance and is not energized in series with thehigh resistance relay 53. Relay 53 is energized and at springs 39 and 57 opens the control circuit of magnet 34 and prepares a circuit for the vertical magnet 64 at springs 39 and 58, also at springs 69 prepares a circuit for the private magnet 67.

The calling subscriber may now call the second digit of the desired number, thereby producing as before a series of interruptions in. the line circuit. Now, however, the line relay transmits a series of impulses to the vertical magnet 64, over the following path: from ground G springs 35, springs 36, winding of relay 37, springs 38., springs 39 and 58, winding of vertical magnet 64, side switch 66 (first position), to battery.

In response to these impulses the vertical through springs 68 and 69, springs 60,

springs 71, winding of private magnet 67 to battery. After the impulses cease the relay 37 dcenergizes and opens the circuit of magnet 67. Upon the denergization of magnet 67 the side switch wipers 66 and 72 are stepped to second position in the usual well known manner.

The calling subscriber may now call the units of final digit of the called number, thereby producing as before a series of interruptions in the line circuit. Now, however, the side switch being in second position, the line relay transmits a series of impulses to the rotary .magnet 65, over the following path: from ground at G springs 35, springs 36, winding of relay 37 springs 38,-springs 39 and 58, springs 73, winding of rotary magnet 65, side switch 66 to battery, The rotary magnet responds to the impulse of currentjn the circuit torotate the wipers 47 48 and 49 until they arrive! at the bank contacts which form the terminals of the desired line. The switch wipers having been rotated into connecthe operation now depends on whether or not that line is busy. Assuming the line to be idle, the test contact engaged by the wiper 48 will be clear of ground and upon the deenergiz'ation of relay 37 the circuit of private magnet will again be broken at tion with the terminals of the desired line, 7

springs 68 and 69. The magnet 67, upon deenerglzing, causes the side switch wipers 66 and 72 to step to third position, thereby closing a circuit for the relay 74 as follows;

from ground G through side switch wiper 72, winding of relay 74, side switch wiper 66, to battery. A branch of the above circuit may be traced as'follows: from ground G through side switch-wiper 72, wiper 41, contact engaged by said wiper to the connector test wiper 48, contact engaged by the wiper 48 through the switching relay and rotary magnet of the line switch individual to the called line (not shown) tobattery.

Relay 74, upon energizing, closes a signaling circuit at springs 77 and 7 8, which may be traced as follows: ground at G generator-7 6, springs 79, springs 80 and 81, conductor 94, springs 83, springs 77, wiper 40, contact engaged by said wiper, connector wiper 47,v thence over the line conductor, through the called substation ringer and back over the other line conductor to connector wiper 49, contact engaged by wiper 43, and said wiper, springs 78, springs 84, upper winding of relay 85 to battery.

I At the connector D by the operation of the I change battery and booster battery in series under the same condition; but it will not qperate from generator current when the can interrupter apparatus the generator 76 is intermittently cut 0H of the ringing circuit and booster battery substituted therefor. The ring cut off relay 85 is so adjusted that it will operate on the current from generator 76 and the exchange battery in series when the\ direct current bridge is closed at the called substation or on current from the exdenser at the called substation is included in bridge thereof.

When the called subscriber responds by removing his receiver which closes a direct current bridge across his line, the relay 85 is energized at once irrespective of the position of the interrupter apparatus, and locks itself over the following circuit: from ground through the off-normal springs 86,- closed on the firstvertical step of the connector shaft, springs 87, lower winding of relay 85, to battery. A branch of the above circuit supplies ground to the lower winding of the back bridge relay 88. To proceed, relay 85, upon energizing, disconnects its upper winding and the interrupter apparatus at springs 84 and 83, and completes the talking circuit through the connector D. Talking battery for the transmitter at substation A is 'supplied from the windings of the line relay 25,

.while the transmitter at the called substationis supplied from the windings of relay 88. The path for voice currents is indicated by heavy conductors and will be readily .understood without further explanation,

Upon deenergizing, line relay 25 breaks the circuit of slow acting release relay-26. Relay 26, upon denergizing, removes ground from the holding circuit extending backto the line switch C and also closes a circuit for the release magnet 89. Bythe former operations the relay 16 of the line switch C is allowed to restore its springs to normal, while the energization of the release magnet 89 results in the restoration of the connector and auxiliary switch to'normal.

It will now be described how the connector D operates when it is attempted to establish connection with a busy line, in which case the test contact engaged by the wiper 48 would have a ground potential upon it, (it being assumed that the called line is in the second group.) When the connector wipers .47, 48 and 49 are rotated into engagement with the contacts forming the terminals of the desired line the relay 37 is energized during the rotation as previously described. As soon as the test wiper 48 arrives at the test contact of the called busy line, and the relay 37 denergizes, the relay 90 will be energized in series with the private magnet 67 over the following path: from ground at this test contact engaged by the wiper 48, through said wiper, contact engaged by wiper 41 and said wiper, side switch wiper 72 (in second position), winding of relay'90, springs and 69, springs 60, springs 71, windlng of private magnet 67 to battery. The private magnet is held energized over this circuit to prevent the side switch from going to third position. Relay 90, upon energizing opens the circuit of the rotary magnet at springs 73, closes a holding circuit for itself and the magnet 67 at springs 91 independent of ground potential at the test wiper, alsoconnects a lead to the busy signaling I to the lower line conductor at springs 92. By the transmission of a distinctive tone to the calling subscriber he is informed that the line which he isattemptingto connect with is busy. VVhereupon he will replace his receiver and the line switch and connector will be released as previously explained.

Supposing that the subscriber at substation A desires to connect with a subscriber in the third group of lines accessible to the connector. D, which is the party line group. He will operate his calling device to interrupt the circuit of line relay 25 three or four times'depending upon what party on the-line is wanted. Assuming that the first digit is three; the wipers 40, 41, 42 and 43 are rotated to connect with the third set of contacts which form the terminals of the connector wipers 50, 51 and 52. The operation of the connector switch is the same as previously described, and ringing current from generator 7 6 will be projected over the called line. However, if the first digit called is four, the wipers 40, 41, 42 and 43 will be. rotated to connect with the fourth set of contacts, which contacts corresponding to the line and test contacts are multipled to the third set of similar contacts. The operations to connect with a called line are the same as previously described with the exception that the low resistance relay 93 isenergized in series with relay 53 and stepping magnet 34. Relay 93, upon energizing, connects ringing current from generator 75 to conductor 94, which generator supplies current of a different frequency from that of generator 76. It is to be understood that the bells on the party lines are bridged across the conductors v line switch C, and the remaining contact for itself at springs 97, from ground through ofi' normal springs 86 independent of ground at contact 95. At springs 98 ground potential is connected tothe lower terminal of relay 53. Assuming that the first trunk to the mainexchange is busy,

then a ground potential will be present at contact '99, which closes a circuit for the stepping magnet 34 as follows: grounded contact 99, wiper 42, springs 55 and 100, springs 62 and 63, interrupter springs 56,

winding of magnet 34 to battery, a branch of the above circuit may be traced from the junction point 101 to the upper terminal of relay 53. The magnet 34 is operated over the above circuit to step the wipers 40, 41, 42 and 43 to the next set of contacts; if this trunk line is busy the magnet 34 will again he energized and this operation will continue until an idle trunk is reached, at which time there will be no ground potential present at the contact which the wiper 42 meets. Relay 53-will he nolonger shorted out and will immediately-energize overthe following circuit; from ground through springs '98, winding of relay 53, junction point 101, springs 56, winding of magnet 34,

,to battery; ,Magnet 34*.is not energized in series with therelay 53 as hereinbefore described. Relay 53, upon energizing at this time, closes circuit for the switching rela and stepping magnet of the line switch which may be traced as follows: from ground through springs 102 and 62, springs 100 and 55, wiper 42, contact 99 (assuming that the first trunk was idle) conductor 103, which corresponds to conductor 32 of line switch C, through the switchin relay and rotary magnet in series of switc C, corresponding to relay 16 and magnet 17 of switch c. ,The switching relay of switch Cv is operated to extend the talking conductors through the switch C to the trunk conductors 104 and 105 terminating in the main exchange in a switch (not shown) which may be similar to the switch D. A circuit is now closed. across the trunk conductors as follows: conductor 104, through the switch C to contact 106, wiper 43, springs 59, springs 108, springs 109 and 110, springs 111 and 112, impedance 113, springs 114, springs 61, wiper 40, contact 107, through switch C, and conductor 105.

The calling subscriber may now proceed to manipulate his calling device in accordance with the next digit of the desired number, thereby producing in the usual manner a series of interruptions in the line circuit. At each interruption the line relay 25 deenergizes momentarily and opens the trunk circuit at springs 114 which causes the line relay of an automatic switch at the main exchange (not shown) to operate in the usual and well known manner to extend the connection to a called line. The line relay 25 in response to the interruptions of its circuit also closes a circuit for the slow relay 37 in series with the resistance R. Relay 37 energizes and retains its armature attracted during the series of impulses and at springs 109 and 115 shorts out the impedance 113 during the transmission of impulses to the main exchange.

The switch C has access to connector switches similar to the connector D, when seized from the main exchange over the trunk conductors 104 and 105.

Having describedmy invention what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

What I claim as my invention is:

1. In a telephone system, an automatic switch, a line leading to said switch, trunk lines accessible thereto, an auxiliary switch individual to said automatic switch for selecting one of said trunk lines, means for transmitting a plurality of series of impulses over said line, and means responsive to the first series of said impulses for causing said auxiliary switch to select one of said trunk lines without operating said automatic switch.

2. In a telephone system, an automatic switch, a line leading to said switch, trunk lines accessible thereto, an auxiliary switch individual to said automatic switch for selecting one of said trunk lines, means forv transmitting. a plurality of series of impulses over said line, means responsive to the first series of said impulses for. causing said auxiliary switch to select one of said trunk lines without operating said automatic switch, and means in said automatic switch for repeating the next series of said impulses over the selected trunk line.

3. In a telephone system, a line, trunk lines, an automatic switch individual to said line, an auxiliary switch individual to said automatic switch for selecting one of said trunk lines, means for transmitting a plurality of series of impulses over said line, means responsive to only one of said series of impulses for causing said auxiliary switch to select one of said trunk lines without operating said automatic switch; and means in said automatic switch for repeating the other series of said impulses over the selected trunk line.

4. In a telephone system, .a line, trunk lines, an automatic switch individual to said line, an auxiliary switch associated with said automatic switch for selecting one of said trunk lines, means for transmitting a pluralityof series of impulses over said line,

a relay in said automatic switch for firstoperating said auxiliary switch to select one of said trunk lines without operating said automatic switch and for thereafter repeating the impulses over the selected trunk line. 5. In a telephone system, aline, an automatic switch individual to said line, an

auxiliary switch individual to said automatic switch having a magnet both dlrectivel and automatically operable for-controlllng the operation thereof, agroup of trunk lines accessible to said auxiliary switch, means for transmitting a series of impulses over said line to operate said magnet to cause said auxiliary switch to select the group of trunk lines, and means for then automatically operating said magnet to cause said auxiliary switch to select an idle one of. said trunk lines.

6. In a telephone system, a line, an automatic switch individual to said, line, an auxiliary switch individual to said automatic switch having a magnet both directivel and automatically operable for controllmg the operation thereof, a group of trunk lines accessible to said auxiliary switch, means for transmitting a series of impulses over said line to operate said magnet to cause said auxiliary switch to select the group of trunk lines, means for then automatically operating said magnet to cause said auxiliary switch to select an idle 85 one of said trunk hues, and means 1n said I 7. In a telephone system, aplurality of 1 groups of lines, a switch for connecting with any line in any group, a line relay for said sw tch, an auxiliary switch for selecting one of said groups, a pair of operating magnets for said first switch, an operating magnet {for said auxiliary switch, means for'operatmg the line relay of said first switch in response to one digit of the called number to operate the operating magnet of said auxiliary switch to causc said auxiliary switch to select a group of lines, and means for thereafter 0 eratin said line relay in response to ot er digits of'the called number to operate said pair of operating magnets to cause said first switch to connect with a line in the selected group.

8. In a telephone system, a plurality of roups of lines, one of said groups consisting of party lines, a switch for connecting with any line in any group, a plurality of sources of ringing current, another switch for selecting a group of lines and for selecting'one of sald sources of current, means for sending a plurality of series of impulses to said first switch corresponding to the digits of. the called number, means responsive to the first digit of the called number for causing said other switch to select a group of lines and a particular one of said sources of current, and means for thereafter operating said first switch in response to Mother digits. of the called number to find the called line and. connect said selected source of ringing current therewith.

9. In a telephone system, a plurality of groups of lines, one of said groups consisting of party lines, a switch for connecting with any line in any group, a plurality of sources of ringing current, another switch in response to other digits of the called number to find the called line and connect said selected source of ringing current therewith.

10. In a telephone system, a line, a switch individual to said line, a plurality of trunking elements in said switch and individual thereto, an auxiliary switch for selecting any one of said trunking elements, a group of trunks accessible to said auxiliary switch but inaccessible to said elements, means for making one or more of said trunks busy, said auxiliary switch having means for automatically rejecting a busy trunk and se- 115 and means for operating said first switch lecting an idle one, and means for transmitting electrical impulses over said km for,

controlling all the operations of said switch.

11. In a telephone system, a line, a switch individual to said line, a plurality of trunking elements embraced in said switch and individual thereto, each one for trunking said first line into connection with any one of a group of other lines, each trunking element being associated with a different group, said switch having means for selecting any one of said trunking elements, a group of trunk lines accessible to said switch, other similar switches having access to said trunk lines whereby the trunk lines may be seized and made busy, said switch also having means for automatically selecting out of said group of trunks one that is not busy and for extending connection from said first line to the selected trunk and making it busy.

12. In a telephone system, a line, an automatic switch individual to said line, a plurality of trunking elements individual to said switch, a group of trunks accessible to said switch, and an auxiliary switch in said automatic switch for selecting a trunking element or selecting an idle trunk.

13. In a telephone system, a line, a switch individual to said line, a plurality of trunking elements embraced in said switch and individual thereto, each one for trunking said first line into connection with any one of a group of other lines, each trunking element being associated with a different group, means in said switch for selecting any one of said trunking elements, a group of trunk lines accessible to said switch, other similar switches having access to said trunk lines whereby the trunk lines'may be seized and made busy, said means also forautomatically selecting out of said group of trunks one that is not busy and for extending connec tion from said first line to the selected trunk and making it busy, said means also for selecting any one of a plurality of sources of signaling current, each source producing current of diiferent character, said different sources for operating difi'erent signals over connections established by way of said trunking elements. ,7

14. In a telephone system, a line, a switch individual to said line, means for operating said switch in -response to impulses of a digit of a called number," trunking elements individual to said switch, said switch having means responsive to said impulses for selecting a rogressively movable trunking element, or selecting an idle trunk out of a roup of trunks some of which are busy and or rejecting busy trunks, or for selecting any one of several sources of signaling current for operating signals by way of said trunking elements. I

15. In a telephone system, a line, a switch.

individual to said line, means for operating said switch. in response to impulses of a digit of a called number, trunking elements individual to said switch, said switch having means responsive to said impulses'for selecting a progressively movable trunking element, for selecting an idle trunk out of a group of trunks some of which are busy, and for rejecting busy trunks, or for selecting any one of several sources of signaling current for operating signals by way of said trunking elements, and means for transmitting impulses over said line for controlling all the operations of said switch.

16. In a telephone system, a connector switch having a plurality of setsof wipers, an auxiliary switch individual thereto, trunk lines leading therefrom, means under the control of said connector switch to cause said auxiliary switch to select an idle one of said trunk lines or one of said sets of wipers,

and means operating thereafter if a trunk line is seized to cause said connector switch to repeat impulses over the selected trunk.

17. In a telephone system, an automatic switch having a plurality of sets of wipers a group of lines accessible to each set of wipers, an auxiliary switch individual to said automatic switch having access to trunk lines, a relay in said automatic switch .operating at one time to cause said auxiliary switch to select a particular set of wipers and operating at another time to cause said auxiliary switch to select an idle trunk in said group of trunk lines, and means for thereafter operating said relay to repeat impulses over the selected trunk.

18. In a telephone system, an automatic switch having a plurality of'sets. of wipers, a group of lines accessible to each set of wipers, one of said groups being party lines, an auxiliary switch individual to said automatic switch, ringing generators of different frequency, means for operating said auxiliary switch to associate any set of wipers with said automatic switch, and for operating said switch to extend a connection to a line in the group associated with said set, said switch also operating to select a particular frequency when the set of wipers is used which has access to a party line group.

19. In a telephone system, an automatic switch, a plurality of wipers for said switch, an auxiliary switch individual to said automatic switch for selecting a particular set of wipers, sources of ringing current of different character associated with said auto-. matic switch, said auxiliary switch responsive to impulses of a digit of a called number to select a set of wipers and at the same time a source of si naling current.

20. In a ti switch, a plurality of groupsof lines accessible thereto, a set of Wipers individual to each group of lines, means in said switch reephone system, an automatic number for operating one of said sets of Wipers to either extend a connection by one of the lines of its associated group or select another set of Wipers for use.

21. In a telephone system, an automatic switch, a plurality of groups of lines accessiole thereto, a set of Wipers individual to each group of lines, means in said switch responsive to impulses of a digit of a called number for operating one of said sets of wipers to either extend a connection by one of the lines of its associated group or select another set of Wipers for use, and means for repeating impulses over the lines of one group.

Signed by me at Chicago, Cook county, Illinois, this 18th day of Februar 1919.

1 JOHN H. HOMRI HOUS. 

